1. Field of the Invention
The present invention relates to the structure for cleaning a print head of an ink jet printer and a device for driving the cleaning structure.
The present invention also relates to an ink jet recording apparatus having a recording head which moves in the direction of width of recording paper, and discharges ink droplets onto recording paper in accordance with print data for printing images, and more specifically relates to a control technology for the recording head cleaning operation to recover from inferior printing of the recording head by absorbing ink through nozzle openings of the recording head.
The present invention is based on Japanese Patent Applications Nos. Hei. 10-18657, Hei. 10-154852 and Hei. 10-339052, which are incorporated herein by reference.
2. Description of the Related Art
In the ink jet printer, liquid ink is supplied from an ink tank to a print head, and forcibly discharged in the form of an ink droplet onto a printing medium, through ink jet nozzles of the print head. Sometimes, some of the ink passages ranging from the ink tank to the ink jet nozzles are clogged with air bubbles to possibly obstruct the ink discharging through the passage. To cope with this, the ink jet printer usually has a xe2x80x9cclogging-check-pattern printing functionxe2x80x9d, and a xe2x80x9ccleaning functionxe2x80x9d. When the former function is exercised, the printer prints a preset clogging check pattern by use of all the nozzles of the print head. A user checks the printed preset pattern to locate a clogged nozzle or nozzles if such defective nozzle is present. The latter function, or the cleaning function, is exercised when the clogged nozzle is located, to suck ink from the clogged nozzle to remove its clogging.
Most of the ink jet printers are designed so as to be capable of printing in monocolor or multi-color mode. To this end, the printer uses four (K (black), C (cyan), M (magenta), Y (yellow)) or larger number of color inks. Further, the printer includes ink tanks and a set of nozzles (e.g., 64 or 128 nozzles), which are respectively provided for those color inks. In a printer using four color inks and having 64 nozzles for each color, the total number of required nozzles is 256, and great.
The clogging check pattern printed out shows the location of a clogged nozzle, if present. Therefore, the user knows which of those nozzles arrayed is clogged. In the event that at least one nozzle is clogged, the user instructs the printer to exercise the cleaning function for removing the clogging. The cleaning operations usually consists of three steps; 1) xe2x80x9cflushingxe2x80x9d for driving the nozzle to discharge the ink, 2) xe2x80x9cwipingxe2x80x9d for wiping out the ink from the nozzle surface, and 3) xe2x80x9csuctionxe2x80x9d for sucking the ink from the nozzles by applying negative pressure to the nozzle. Thus, the cleaning operation is complicated. Of those cleaning operation steps, the xe2x80x9csuctionxe2x80x9d process is performed such that 1) the print head is moved to a home position, 2) the entire print surface of the print head is capped with a rubber cap, and 3) the ink is sucked from all the nozzles of the print head thus capped.
In order to solve these problems the ink jet recording apparatus has capping means for sealing the nozzle openings of the recording head in a non-print mode and a cleaning mechanism for cleaning a nozzle plate as the need arises. This capping means functions as a cover preventing ink at said nozzle openings from drying. Said capping means also has a function to solve clogging of the nozzle openings with absorbing ink through the nozzle openings by sealing the nozzle plate with a capping member and applying negative pressure from a suction pump when clogging occurs at the nozzle openings.
The forcible ink suction and discharge process executed to solve clogging of the recording head is generally called the cleaning operation. The cleaning operation is performed when resuming the printing operation after a long halt or when the user turns on a cleaning switch in order to solve clogging of the recording head. Said operation is followed by the wiping operation with a wiping member comprised of elastic plates such as rubber after discharging ink droplets by applying negative pressure.
In this kind of recording apparatus, said recording heads for black ink and color inks are also disposed on one nozzle plate. A black ink cartridge and a color ink cartridge are provided on each recording head for supplying ink. With regard to this kind of recording apparatus for public use, said each cartridge is mounted directly to the top of each recording head respectively.
FIG. 32 is a cross section showing the state that an ink cartridge is mounted on the top of the recording head and the nozzle plate of the recording head is sealed with capping means ascended form the lower part of the recording head.
Specifically, reference numeral 308 in FIG. 32 denotes the ink cartridge. A film member (not shown) is adhered to an ink supply port 308a of the ink cartridge 308 so as to prevent ink solvent form vaporizing while ink is stored.
When a new cartridge is installed, the cartridge 308 can be mounted just by thrusting in a manner in which an ink supply port 308a of the ink cartridge 308 is placed downward in the opposite side of a supply needle 331, which is hollow and set up upward beyond the back of the recording head 307. With this operation, said ink supply needle penetrates said film adhered to the ink supply port 308a. Thus, rubber seal member 308b disposed inside the ink supply port is closely connected with the ink supply needle, thereby ink is supplied to the recording head 307 from the cartridge 308.
The capping member 310 arranged in a non-print section of the apparatus ascends from the lower part so as to seal the nozzle plate of the recording head 307 after the carriage mounting said recording head 307 moves to the non-print section. An ink suction port 324 connected to a suction pump (not shown) and an air opening 325 connected to an air valve (not shown) are disposed on the bottom of said capping member 310. When the suction pump operates with the air valve connected to the air opening 325 closed, the cleaning operation is executed for sucking ink from the nozzle openings of the recording head. When the suction pump operates with the air valve open, discharged ink within the capping means 310 can be discharged into a discharge ink tank (not shown).
In the recording apparatus as described above, when replacing an ink cartridge, said capping means seals the nozzle plate of the recording heads and the suction operation is performed for absorbing ink through the nozzle openings by applying negative pressure from the suction pump (the cleaning operation for replacement). Thereby bubbles entered at the time of connecting the ink cartridge and the ink supply needle, are removed. This suction operation discharges said bubbles entered into the recording head during replacement of the cartridge, so that poor printing, such as the so called missing dots, can be avoided.
As described above, in the event of clogging of the nozzle, to remove the clogging, all the nozzles must be subjected to the suction process even if the clogged nozzle is located. This is due to several reasons.
One of the reasons is as follows. The clogging is formed through a complicated mechanism. Therefore, if only the clogged nozzle is sucked, the clogging is not always removed. If so, a natural conclusion is that the sucking of all the nozzles will reliably remove the clogging of the nozzle. However, the sucking of all the nozzles leads to consumption of much ink. The cost of the ink consumption is for the user to bear.
For example, when a black ink cartridge is replaced, ink suction is executed not only through the nozzle openings for discharging black ink but from the nozzle openings for jetting cyan, magenta, and yellow inks as well. Thus, there was a problem that color inks were unnecessarily consumed
Moreover, since each nozzle opening absorbs ink equally, rise of negative pressure is delayed and all bubbles are washed away. Consequently, there was a need to absorb and discharge a volume of ink several times that of the capacity of the head.
Except for said cleaning operation for replacement, when specific ink dots are missing, the ink suction operation absorbing ink equally from all nozzle openings is necessary even after the cleaning operation is executed. Thus, ink consumption of each ink cartridges unnecessarily increases and the user is forced to bear the running costs.
Furthermore, when meniscuses at the nozzle openings are formed during the cleaning operation, ink bubbles discharged into the capping means adhere to the nozzle plate. These bubbles are absorbed through the nozzle openings and destroy the meniscuses formed at the nozzle openings. This result in causing disorder of ink droplet""s path and missing dots.
Some places where air bubbles are likely to stay are present in the ink passage ranging from the ink tank to the ink jet nozzle. One of the places is a filter chamber located downstream of and near to the ink tank. In case where a replaceable ink cartridge is used for the ink tanks, the filter chambers are provided with needle tubes. When the ink cartridge is set to the printer, the needle tubes are thrust into the related ink tanks. During the thrusting, air bubbles possibly enter the filter chamber through a cylinder-piston action by the ink tank and the needle tube.
Generally, one ink tank supplies ink to a number of ink jet nozzles, and an ink supply passage is branched at a location downstream of the filter chamber to have a number of ink passages. The branching of the ink supply passage leads to an increase of its cross section area. The result is that an ink flow rate in each branched ink passage is reduced, and the force acting to drive the air bubbles out of the filter chamber is weak or insufficient.
Accordingly, an object of the invention is to effectively drive air bubbles out of the filter chamber through the branched ink supply passages to thereby prevent air bubbles from entering through nozzle openings.
In view of such problems as described above, the object of the present invention is to provide an ink jet recording apparatus which can perform the ink suction operation only through the required nozzles during the cleaning operation for replacement executed after replacing an ink cartridge, and also can reduce the volume of absorbed ink during the ink cleaning operation.
According to one aspect, there is provided an ink jet printer comprising: at least one ink chamber; a print head having a plurality of ink jet nozzles and being connected to the ink chamber; a print controller for driving the print head in order to print; and a capping device for covering the ink jet nozzles of the print head.
The capping device comprises: a cap component having a plurality of cavities for sorting the ink jet nozzles into a plurality of nozzle groups by ink chamber unit, thereby capping all ink jet nozzles corresponding to at least one ink chamber by nozzle group unit; at least one pipe being connected to the cavities of the cap component for supplying negative pressure to the cavities; and a suction controller for controlling the supply of the negative pressure through the pipe to the cavities, thereby supplying the negative pressure independently by every cavity, whereby the suction controller sucks the ink from the ink jet nozzles independently by the nozzle group unit.
In a preferred embodiment of the ink jet printer, the suction controller supplies the negative pressure to one arbitrary cavity of the cap component so as to suck the ink from the ink jet nozzles independently by the nozzle group unit, and all remaining cavities which correspond to one common ink chamber with the arbitrary cavity are sealed.
In another embodiment, the suction controller supplies the negative pressure to all the cavities corresponding to one common ink chamber simultaneously.
In yet another embodiment, a plurality of the ink chambers are provided in the printer, and the cap component has a dimension and number of cavities for capping all of the ink jet nozzles connected to all ink chambers.
In still another embodiment, the cap component comprises one of an integral unit and a plurality of sub-units divided according to the nozzle groups sorted by the ink chamber unit.
In a further embodiment, a plurality of the ink chambers are provided in the printer, and the cap component does not have a dimension and number of cavities for capping all of the ink jet nozzles connected to all ink chambers, and the ink jet printer further comprising a second cap component capping all of the ink jet nozzles at a stretch.
In a still further embodiment, a plurality of the nozzle groups are arranged in a recording medium transporting direction.
In another embodiment, the cap component includes the number of chambers equal to that of the nozzle groups, and caps all the nozzle groups of the print head simultaneously.
In yet another embodiment, one nozzle group is divided into at least two sub-groups of nozzle (in an extreme case, one sub-group consists of one nozzle), and the cap component includes at least two cavities and simultaneously caps those sub-groups.
In still another embodiment, pipes connected to the cavities include valves for closing and opening the pipes. By selectively opening the valves, ink is selectively sucked from the nozzle groups.
In a further embodiment, the pipes connected to the cavities include negative pressure sources, independently operable.
In an additional embodiment, two or larger number of the nozzle groups of the print head are connected to one ink chamber. The cap component includes two or larger number of the cavities so as to simultaneously cap two or larger number of the nozzle groups connected to one ink chamber. Negative pressure is selectively supplied to those cavities. At this time, the remaining cavities are closed (by closing the valves of the pipes associated therewith or applying low negative pressure thereto), thereby preventing air bubbles from entering the remaining nozzle groups.
In another embodiment of the ink jet printer, at least two nozzle groups of the print head are connected to one chamber, and ink is sucked from the two or larger number of nozzle groups connected to the chamber.
In an additional embodiment, the suction controller includes a selective suction portion for supplying negative pressure to one cavity selected from the cavities, and an all-nozzle suction portion for supplying negative pressure to all of the cavities.
In another embodiment, the suction controller includes a selective suction portion for supplying negative pressure to one cavity selected from the plural number of cavities so as to suck ink from the selected cavity, and an all-nozzle suction portion for supplying negative pressure to all of the cavities so as to suck ink from all of the cavities.
In yet another embodiment, the suction controller controls the supply of negative pressure in accordance with clogged nozzle information indicative of a location of a clogged nozzle.
In still another embodiment, the clogged nozzle information includes information indicative of the ink chamber connected to a clogged nozzle, the number of clogged nozzles, and a location of the clogged nozzle on the print head.
In an additional embodiment of the ink jet printer, the suction controller includes a selection table containing a plural number of control guidance corresponding to a variety of clogged nozzle information, and controls the supply of negative pressure in accordance with a specific control guidance, which correspond to the clogged nozzle information, selected from the selection table.
In a further embodiment, the suction controller selects a selective suction mode or an all-nozzle suction mode in accordance with the clogged nozzle information received, and when the selective suction mode is selected, the suction controller sucks ink from at least one nozzle group selected from the plural number of nozzle groups, and when the all-nozzle suction mode is selected, the suction controller simultaneously sucks ink from all of the nozzle groups.
Further, the print controller may include a check pattern print portion for printing a predetermined clogging check pattern used for locating a clogged nozzle by driving the print head.
The ink jet printer may further comprises pattern reading means for reading a printed clogging check pattern to locate a clogged nozzle and to send resultant clogged nozzle information to the suction controller.
The ink jet printer may further comprise input means, operated by a user, for entering clogged nozzle information to the ink jet printer.
In a further embodiment, the ink jet printer is connected to a host controlling device, and the suction controller receives clogged nozzle information from the host controlling device.
In the ink jet printer, the suction controller receives information designating a specific nozzle group or a specific chamber, and supplies negative pressure to a chamber associated with the specific nozzle group or the specific chamber in accordance with the designating information.
The ink jet printer is connected to a host controlling device, and the suction controller receives the designating information from the host controlling device.
According to another aspect of the invention, there is provided a printing system including an ink jet printer and a host controlling device for controlling the ink jet printer. The ink jet printer is constructed described above, and sucks ink from the nozzles of the print head every nozzle group. The host controlling device sends to the ink jet printer selection information necessary for selecting a nozzle group to be sucked from the nozzle groups.
In a preferred embodiment of the printing system, the host controlling device includes a commanding portion for commanding the ink jet printer to print a predetermined clogging check pattern, a user input means by which a user enters user input information indicative of clogged nozzle information, and a selection information generator for generating the selection information on the basis of the user input information entered by the user interface.
In another embodiment of the printing system, the user interface displays a clogging check pattern image on a user interface screen of the host controlling device, and the user enters the user input information by pointing a location on the displayed clogging check pattern image, which corresponds to the location of the clogged nozzle.
According to a further aspect of the invention, there is provided a data storing medium, accessible by a computer, storing a program for executing a process to detect a defective dot forming element of those dot forming elements in a printer, wherein the process comprising the steps of: instructing the printer to print a predetermined clogging check pattern; displaying a clogging check pattern image on a user interface screen of the computer; and specifying the defective dot forming element in a manner that the user points to a location in the displayed clogging check pattern, which corresponds to the defective dot forming element.
According to an additional aspect of the invention, there is provided a data storing medium, accessible by a computer, storing a program for executing a process to instruct an ink jet printer having a number of ink jet nozzles to clean the nozzles, wherein the ink jet printer selectively performs an ink saving cleaning process or a normal cleaning process, the ink saving cleaning process is executed through a selective suction operation to suck ink from only at least one nozzle selected from the ink jet nozzles at any time, and the normal cleaning process is executed through a all-nozzle suction operation for simultaneously sucking ink from all of the ink jet nozzles, and the cleaning instruction process includes a step of displaying an image requesting a user to select the ink saving cleaning process or the normal cleaning process on a user interface screen of the computer, a step of instructing the ink jet printer to execute the ink saving cleaning process or the normal cleaning process selected, by the user, on the user interface screen of the computer.
According to an additional aspect of the invention, there is provided a control method for an ink jet printer having a print head having a number of ink jet nozzles sorted into a plural number of nozzle groups, and a capping device for selectively sucking ink from the nozzle groups by selectively capping the nozzle groups, comprising the steps of: printing a predetermined clogging check pattern and causing a user to locate a clogged nozzle or nozzles; visually presenting a clogging check pattern to the user; obtaining information indicative of the clogged nozzle in a manner that the user points to a location in the displayed clogging check pattern, which corresponds to the clogged nozzle in the printed clogging check pattern; selecting one nozzle group from the nozzle groups on the basis of the clogged nozzle information obtained; and sucking ink from the selected nozzle group.
As well known, a computer program implementing the present invention may be installed in or loaded into the computer by any of various media, e.g., the disk storage, the semiconductor memory, and the communication line.
In another preferred embodiment of the present invention made in order to accomplish the object above, there is provided an ink jet recording apparatus, mounting a ink jet recording head for discharging ink droplets through nozzle openings with ink supplied from an ink cartridge, and capping means for sealing the nozzle openings of said recording head and absorbing ink droplets through the nozzle openings. Said ink jet recording apparatus contains: a valve unit which is disposed between said ink cartridge and the nozzle openings of the recording head for opening and closing the ink supply path between the ink cartridge and the nozzle openings; valve opening/closing control means for controlling opening and closing of said valve unit, interlocked with the cleaning operation to absorb ink droplets through the nozzle openings, with sealing the nozzle openings of the recording head with said capping means.
The valve unit is used to execute the above-mentioned method of selectively sucking ink from the nozzle groups.
In another preferred embodiment of the present invention, there is provided an ink jet recording apparatus, mounting ink jet recording head for discharging different color ink droplets from each nozzle opening with ink supplied from the ink cartridge, and capping means for sealing each nozzle opening of said recording head and absorbing ink droplets through the nozzle openings. Said ink jet recording apparatus contains: a plurality of valve units which are disposed respectively between said ink cartridge and each nozzle opening of the recording head and severally opens and closes ink supply path between the ink cartridge and the nozzle openings; valve opening/closing control means for controlling opening and closing of said each valve unit, interlocked with the cleaning operation to absorb ink droplets trough the nozzle openings, with sealing the nozzle openings of the recording head with said capping means.
In this case, it is desirable that said valve opening/closing control means has options, full-open mode for opening all valves of each valve unit, full-close mode for closing all valves of each valve unit, and alternative valve open mode for opening just one valve by selecting one valve unit alternatively.
Further, it is desirable that said each valve unit can be selected out of said full-open mode, full-close mode, and alternative valve open mode, interlocked with rotational drive by one actuator.
Moreover, in this preferred embodiment, said valve units are positioned in a black ink supply path, cyan ink supply path, magenta ink supply path, and yellow ink supply path respectively.
In another preferred embodiment of the present invention, said valve units are mounted on the carriage together with said ink cartridges and the recording head, and reciprocate along a guide member.
Further, it is desirable that head filters are arranged in the ink supply paths between said valve units and the nozzle openings of the recording head.
Also, in a preferred embodiments of the present invention, said valve units are arranged with at least a pair of ink connecting hole penetrating in the orthogonal direction of the axis of the shaft, disposed across said ink supply paths.
Besides, in a preferred embodiment of the present invention, said capping means is comprised of single capping member which can seal all nozzle openings for ejecting different color ink droplets respectively.
In preferred embodiment of the recording head cleaning control method in a ink jet recording apparatus according to the prevent invention mounting: an ink jet recording head for discharging ink droplets through nozzle openings after being supplied ink from an ink cartridge; capping means for sealing the nozzle openings of said recording head to absorb ink droplets through the nozzle openings; a valve unit arranged between said ink cartridge and the nozzle opening of the recording head for opening and closing the ink supply path between the ink cartridge and the nozzle opening. Said recording head cleaning control method comprising the steps of: in a state said valve unit closed, sealing the nozzle openings of the recording head with said capping means and applying negative pressure within the capping means; in said step with applying negative pressure within the capping means, opening said valve unit to absorb ink through the nozzle openings of the recording head.
In this case, following said ink suction step, it is desirable to further arrange a step for closing the valve unit to prevent air bubbles generated by discharged ink within the capping means by said ink suction step, from being pulled into the nozzle opening of the recording head.
In another preferred embodiment of the recording head cleaning control method in a ink jet recording apparatus according to the prevent invention mounting: an ink jet recording head for discharging different color ink droplets through each nozzle opening after being supplied ink from an ink cartridge; capping means for sealing each nozzle opening of said recording head and absorbing ink droplets through the nozzle openings; a plurality of valve units arranged between said ink cartridge and each nozzle opening of the recording head for opening and closing the ink supply path between the ink cartridge and each nozzle opening respectively. Said recording head cleaning control method comprising the steps of: in a state said each valve unit closed, sealing the nozzle openings of the recording head with said capping means and applying negative pressure within the capping means; in said step with applying negative pressure within the capping means, opening all valve units or a part of said each valve unit and absorbing ink through the nozzle openings of the recording head.
In this case, following said ink absorbing step, it is desirable to further arrange a step for closing all valve units to prevent air babbles generated by discharged ink within the capping means by said ink absorbing step, from pulling into the nozzle openings of the recording head.
According to the ink jet recording apparatus and the record head cleaning control method therein as described above, the valve units arranged on the ink supply paths between the ink cartridges and the nozzle openings, are controlled opening and closing by capping means, interlocked with the cleaning operation for absorbing ink droplets through the nozzle openings.
Therefore, for example, during the cleaning operation for replacing a cartridge, it is possible to discharge entered air bubbles immediately after absorbing ink at the time of loading the cartridge, by controlling said valve units to open valves in a state that a suction pump operates and sufficient negative pressure is applied. In this case, applying sufficient negative pressure within the capping unit in advance enables air bubbles to move quickly and force them to discharge through the nozzle openings. Consequently, the volume of discharging ink can be reduced.
Arranging a valve unit in accordance with each nozzle opening for jetting different color inks enables only required nozzle opening to execute the cleaning operation, for example, by controlling the valve unit corresponding to the nozzle opening where missing dots occur.
Further, exploring a sequence for controlling opening valves of each valve unit after performing the ink suction operation can remove a problem that ink bubbles discharged into the capping means adhere to the nozzle plate of the head, thus air bubbles absorbed through the nozzle openings destroy meniscuses.
Features and advantages of the invention will be evident from the following detailed description of the preferred embodiments described in conjunction with the attached drawings.